A method used in a communication system including a base station and a terminal, the method includes: transmitting from the base station to the terminal a control channel with use of a control channel format selected from among a plurality of control channel formats, each including modulation scheme information, according to whether Multiple Input Multiple Output (MIMO) transmission is applied or not, and receiving the control channel by the terminal, wherein a number of bits indicating a modulation scheme included in a control channel format to be selected when the MIMO transmission is applied is greater than that included in a control channel format to be selected when the MIMO transmission is not applied.